Machine tool for plastic shaping or fashioning

ABSTRACT

A machine tool for plastic shaping or fashioning by hammering, forging, pressing, etc. in which the shaping is accomplished by means of rocking levers having arms of different lengths, with the tools for effecting the working strokes being carried by the shorter arms and being driven by the longer arms.

United States Patent Ribback 1 June 13, 1972 MACHINE TOOL FOR PLASTIC SHAPING OR FASHIONING Bernd Ribback, Rue de Mertert 48, Wasserbillig, Luxembourg [22] Filed: April28, 1969 [21] Appl.No.: 819,912

[72] inventor:

[58] Field 0! Search ..72/76, 402

[56] References Cited UNITED STATES PATENTS 3,263,478 8/1966 Brauer et al. "72/402 Primary Examiner-Lowell A. Larson Attorney-Holman & Stern [57] ABSTRACT A machine tool for plastic shaping or fashioning by hammering, forging, pressing, etc. in which the shaping is accomplished by means of rocking levers having arms of different lengths, with the tools for eflecting the working strokes being carried by the shorter arms and being driven by the longer am-is.

3 Claim, 2 Drawing figures PATENTEDJUH 1 3 m2 SHEET 10F fill L III III PATENTEDJun 13 I972 SHEET 2 BF 2 ZAA M D wwly w ATTORNEYS I MACHINE TOOL FOR PLASTIC SHAPING OR FASHIONINGv BACKGROUNDOF THE INVENTION chuck-The workpieces are introduced from the rear into the.

hollow spindle, clamped, turned, advanced, retracted, unclamped and removed. Such rotatable feeding assemblages are extremely complex and must be connected to the molding machine per se. Moreover, the rotatable introduction process frequently consumes more time than the plastic fashioning or shaping proper. In pipes or conduits whose weight will permit a manual feed, a higher output is realized with a manual feed than with a mechanical feed. In addition, there also bars whose length and flexibility do not permit rotation and whose walls are so thin that such workpieces can no longer be clamped. a

It is also known to feed the work material by means of parabolic helical rollers but this type of feed is rather limited in view of the fact there is only linear contact between the workpiece and the driving rollers.

In all of the known feeding assemblages, it not possible to feed by mechanical means, stirrup like or U-shaped pipes whose ends are to be reduced.

SUMMARY or THE INVENTION BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a view partly in longitudinal section and partly in elevation of a machine tool embodying the invention, and

FIG. 2 is a front elevational view of the machine tool illustrated in FIG. I.

DETAILED DESCRIPTION OF THE INVENTION Referring to the drawings, there is illustrated a machine casing or housing 6 within which levers L are mounted and through which the plastic, shaping or fashioning is effected by hammering, forging,- pressing, etc. More particularly, each lever is adapted to swing about a pivot 4 and includes a short arm 1 and a long arm 3. Each short arm 1 carries a tool and tool holder 2 and each lever receives its drive via the long arm 3 for swinging movement about the pivot 4 so that the tools may execute their working strokes. It will be noted that the levers L and the tool holders are mounted for rotation about a tools are readily accessible exteriorly of the casing 6. This particular arrangement of the tool holders and tools is particularly efiicacious for plastic shaping in that the tool holders andtools are freely accessible from three sides.

It is advantageous that the levers L be arranged in a longitudinal direction parallel to the axis 5 and that the levers be pivotabl mounted on one end 7 of a hollow shaft 8 rotatably mounte in the casing 6. The shaft 8 functions to entrain the pivots 4 and as a consequence the levers L during the rotary movement about the axis 5.

A drive for effecting the working strokes of the levers L with their tools rotates freely on the hollow shaft 8. As illustrated in the drawings, a driven eccentric bushing 9 rotates freely on the shaft 8 and is provided with aforce locking connection with ends 10 of the long arms 3 of the levers for providing the working strokes. The rotation of the bushing 9 on the shaft 8 is accomplished'by means of a motor driven pulley and rope or belt assemblage denoted generally as 11. The drive for the levers L about the shaft 8 for setting the shaping axis in rotation is effected by a motor-driven rope or chain type transmission indicated generally as 12. This arrangement means that the drives 11 and 12 are separated from each other for rotation of the levers L about the axis 5 as well as for the development of the working strokes.

The machine tool is not impaired by the fact that the drives 1 1 and 12 are coupled with each other for mutual engagement and disengagement and the coupling of the drives 11 and 12 can be'so designed that the tools can operate with any number of strokes and independently thereof can rotate the shaft 8 and thus the levers L about theaxis 5. It is also within the scope of the invention to provide a coupling between the drives 11 and 12 which is so constructed that the rotary movements of the levers L and their tools are effected in dependence upon their stroke movements since rotation takes place only, for example, if the shaping tools move apart.

lclaim:

1. In a machine tool for plastic shaping by hammering, forging, pressing and the like, comprising a casing, a hollow rotatable shaft mounted in said casing and defining a working axis, and a plurality of cooperating pivotable levers each having a short arm carrying a working tool and a long arm on opposite sides of its pivot point, the improvement wherein said hollow rotatable shaft is rotatably mounted at its opposite ends in said casing by respective bearing means defining a pair of axially spaced radial planes, each of said levers being pivotably mounted to said rotatable shaft adjacent one end thereof by pivotal means located in one of said radial planes, for rotation about said working axis with said rotatable shaft.

2. The improvement of claim 1, further comprising an eccentric bushing mounted on said rotatable shaft intermediate the ends thereof for rotation relative to said shaft, said eccentric bushing being coupled force-locked with the free ends of the respective long anns of said pivotable members to effect the working strokes of the levers, and means for effecting rotation of said eccentric bushing relative to said shaft to thereby effect the working stroke of said pivotable levers.

3. The improvement of claim 2, wherein said short arms of the pivotable levers extend outwardly of the casing, the working tools being located outside of the casing.

l II i 

1. In a machine tool for plastic shaping by hammering, forging, pressing and the like, comprising a casing, a hollow rotatable shaft mounted in said casing and defining a working axis, and a plurality of cooperating pivotable levers each having a short arm carrying a working tool and a long arm on opposite sides of its pivot point, the improvement wherein said hollow rotatable shaft is rotatably mounted at its opposite ends in said casing by respective bearing means defining a pair of axially spaced radial planes, each of said levers being pivotably mounted to said rotatable shaft adjacent one end thereof by pivotal means located in one of said radial planes, for rotation about said working axis with said rotatable shaft.
 2. The improvement of claim 1, further comprising an eccentric bushing mounted on said rotatable shaft intermediate the ends thereof for rotation relative to said shaft, said eccentric bushing being coupled force-locked with the free ends of the respective long arms of said pivotable members to effect the working strokes of the levers, and means for effecting rotation of said eccentric bushing relative to said shaft to thereby effect the working stroke of said pivotable levers.
 3. The improvement of claim 2, wherein said short arms of the pivotable levers extend outwardly of the casing, the working tools being located outside of the casing. 